There is a short fall in all current automated pipe handling equipment for the well service industry. There is a need to vary the height of a V-door on well service rig automated pipe handling systems, and other automated pipe handling applications were variable V-door height is required. Specifically, when performing well servicing, different wells, locations, or service processes require different blow-out preventer (“BOP”) systems, wellhead configurations, or other well control requirements causing the work floor on the service rig to be positioned at varying heights. The work floor height of a service rig must change to accommodate these different applications, and also requires the V-door height to change accordingly. Existing designs use a telescoping tube in tube designs, or fixed designs that are prone to have pipe size and weight restrictions, as well as transition problems were these tubes meet. These designs also require that the V-door be fixed in position at rig-up, or pivot/fold into position, and further require a crane to perform these functions. There is also a need for a positive drive skate system to move tubulars to and from the drilling rig work floor, and to provide the ability to “grab” the tubulars and pull them along the horizontal direction of the catwalk to enable kicking, indexing or positioning of these tubular. This is especially so when pulling tubulars without conventional upsets or thread protectors, ie, “slick pipe”, along the surface of the catwalk deck to position the tubulars for kicking, indexing or delivery. Existing grabbers do not clamp the pipe between the skate v-plate with sufficient force to overcome the friction required to pull the pipe rearward.
It is, therefore, desirable, to provide an automated pipe-handling catwalk that addresses the shortcomings in current pipe-handle equipment, as noted above.